1. Field of the Invention
The present invention relates generally to the field of computers and computer accessories. More specifically the present invention relates to a chair arm-mounted tray apparatus for supporting an item such as a keyboard in front of a user seated on a chair. The tray apparatus includes a panel defining a support deck on which the item is placed and a deck support frame fastened to the deck, the deck support frame having chair arm engaging means which removably secures the apparatus to the arms of a chair. The support frame positions the deck forwardly of the chair at an adjustable height and at an adjustable orientation relative to horizontal for ergonomic positioning of user arms and hands while the user operates a computer keyboard or mouse resting on the deck.
The deck support frame includes parallel and laterally spaced apart telescoping frame arms removably secured to chair arms by the chair arm engaging means. The chair arm engaging means preferably takes the form of first and second arm straddles in the form a U-shaped member defining a pair of spaced apart straddle tines. The straddle tines fit around each chair arm, pointing outwardly from the middle of the chair. As the frame arms pivot downwardly with their own weight as well as the weight of the deck and supported item, the tines rotate into abutting contact with the upper and lower surfaces of each chair arm, stopping further frame arm pivoting and thus supporting the frame arms and deck as the chair arms project forwardly and upwardly from the seat of the chair. Each arm straddle includes a clutch pivot joint at which the arm straddle engages the adjacent frame arm.
2. Description of the Prior Art
There have been various tray devices for connecting to or hanging from existing structures for supporting a wide variety of items, such as food at a drive-in restaurant. An example of a chair attached computer keyboard holder is found in Trimnell, U.S. Pat. No. 5,893,707, issued on Apr. 13, 1999. A problem with Trimnell is that it connects to a only certain type of chair legs not found on many chairs and is apt to be bumped by user feet. Another example is that of Yancz, et al., U.S. Pat. No. 5,356,059, issued on Oct. 18, 1994 for a basket or tray for attachment to a wheelchair. Once again, the attachment means appear to require the structure of a wheelchair, making its use very limited in the business world.
It is thus an object of the present invention to provide an arm chair mounted item support apparatus which can be removably secured to the chair arms so that an item supporting tray is in front of a seated user.
It is another object of the present invention to provide such an apparatus which includes means for altering and selecting the tray elevation and forward tray distance from the user.
It is still another object of the present invention to provide such an apparatus which includes means for altering and selecting the tilt of the tray forwardly or rearwardly for ergonomic use.
It is finally an object of the present invention to provide such an apparatus which is light weight, compact to store and transport, sturdy and inexpensive to manufacture.
The present invention accomplishes the above-stated objectives, as well as others, as may be determined by a fair reading and interpretation of the entire specification.
A chair arm-mounted tray apparatus is provided for mounting on chair arms of a chair having a chair seat, for supporting an item, including an item support deck for supporting an item; and a deck support frame fastened to the support deck, the deck support frame having a chair arm engaging mechanism for removably securing the apparatus to the arms of a chair; so that the deck support frame positions the deck forwardly of the chair at an adjustable height and at an adjustable orientation relative to horizontal.
The deck support frame preferably includes two parallel and laterally spaced apart telescoping frame arms removably secured to the chair arms by the chair arm engaging mechanism, the frame arms each having a frame arm forward end adjacent to the deck and a frame arm rearward end adjacent to the chair. The deck support frame alternatively includes at least one telescoping frame arm removably secured to a chair arm by the chair arm engaging mechanism, the frame arm having a frame arm forward end adjacent to the deck and a frame arm rearward end adjacent to the chair. The chair arm engaging mechanism preferably includes first and second arm straddles, each configured as a substantially U-shaped member defining a pair of spaced apart straddle tines; so that the straddle tines fit around each chair arm, facing generally outwardly from the middle of the chair, and so that the frame arms pivot downwardly with their own weight and the weight of the deck and thereby the tines rotate into abutting contact with upper and lower surfaces of each chair arm, stopping further frame arm pivoting and thus supporting the frame arms and the deck.
Each arm straddle preferably includes a clutch pivot joint at which the given the arm straddle engages the adjacent frame arm, each clutch pivot joint including a threaded straddle shaft extending from each arm straddle toward the opposing arm straddle and a straddle clutch disk facing toward the opposing arm straddle, each frame arm having a chair end including a shaft port for receiving and passing the adjacent straddle shaft, and having a clutch surface facing the adjacent straddle clutch disk; and a straddle nut screwed onto each threaded straddle shaft until the frame arm chair end clutch surface firmly abuts and engages the corresponding straddle clutch disk, preventing relative rotation between each frame arm and each arm straddle; so that the angle of the frame arms relative to horizontal can be adjusted as needed by the user by loosening the straddle nuts enough that the clutch surface and the clutch disk of each arm straddle disengages to permit frame arm pivoting about the straddle shafts, and so that when the desired frame arm angle is achieved, the straddle nuts may be again screwed tight to bring the clutch surfaces and the clutch disks into engaging mutual abutment. The straddle nut preferably has an elongate exterior to function as a handle for the user to grip while rotating the given the straddle nut. The clutch surface and the clutch disk each have engaging surfaces configured to define coaxially centered radial undulations so that the crest of each of the undulations on the given clutch disk fits engagingly into a valley of an undulation in the opposing the clutch surface; so that firm abutment of each clutch surface and the corresponding clutch disk prevents relative rotation of the clutch disks and clutch surfaces, because an abutting side of each valley blocks rotational movement of the adjacent opposing crest.
Each frame arm preferably includes two telescoping inner and outer arm tubes, each outer arm tube forming the rearward segment of each frame arm and being connected at the outer arm tube rearward end to the adjacent arm straddle through one of the clutch pivot joints, and the corresponding inner arm tube forms the forward segment of each frame arm and the inner arm tube forward end. The apparatus preferably additionally includes a set screw extending through a threaded port in the forward end of each outer arm tube for screwing against the corresponding inner arm tube to releasibly fix the extension of each frame arm.
The apparatus preferably additionally includes a deck mounting assembly interconnecting the deck and the frame arms. The deck mounting assembly preferably includes a deck cylinder extending between the forward ends of the frame arms and connected to the deck, the deck cylinder including a deck axle secured to and extending axially and longitudinally outward from the deck cylinder; a deck axle port in the forward end of each frame arm receiving and passing one of the deck axles; and a deck cylinder clutch mechanism for releasibly securing the deck cylinder and the connected deck against rotation about the longitudinal axis of the deck cylinder relative to the frame arms.
The deck cylinder clutch mechanism preferably includes a cylinder clutch engaging surface on each longitudinal end of the deck cylinder; a frame arm clutch engaging surface on each frame arm forward end adjacent to the frame arm port directed toward the deck cylinder; external threads on the deck axles; and a deck axle nut sized to screw onto the threads on each deck axle; so that each frame arm port is fitted over the corresponding and adjacent deck axle and a deck axle nut is screwed onto each deck axle to bring the corresponding frame arm clutch engaging surface into engaging contact with the corresponding cylinder engaging surface, thereby inhibiting relative rotation between the deck cylinder and the frame arms about the deck cylinder longitudinal axis.
The apparatus preferably additionally includes at least one spacer tube for fitting around one of the deck axles between the deck cylinder and the corresponding frame arm forward end for positioning the frame arms a greater lateral distance apart from each other to correspond to the lateral spacing between chair arms of chairs having a wider spacing than the length of the deck cylinder; the at least one spacer tube having spacer tube clutch engaging surfaces at each spacer tube longitudinal end for engaging the cylinder clutch engaging surface and the corresponding frame arm clutch engaging surface.
The spacer tube clutch engaging surface, and the cylinder clutch engaging surface and the frame arm clutch engaging surface are each preferably configured as surface undulations extending radially from the longitudinal axis of the deck cylinder; so that the crests of the undulations of one clutch engaging surface fit into the valleys of an opposing and adjacent clutch engaging surface which laterally abuts each crest and thereby prevents relative rotation between the clutch engaging surfaces. The apparatus preferably includes several the spacer tubes of various different lengths for setting the lateral spacing of the frame arms for a variety of different chair lengths.